1. Field of the Invention
The invention concerns an axial locking device for turbomachine (i.e., turbine and compressor) blades, which radially locks the blades by their roots in axial grooves formed in the rim of the rotor disk and axially locks the blades by locking devices which work together with the blade roots and the rotor disk.
2. Description of the Prior Art
Many axial blade locking devices require rather complicated machining of either the rim or the blade shank and sometimes both. Generally notched teeth are positioned on the upper face of the disk and perpendicular to this face. Locking parts are positioned in the notches against the blade root to prevent axial movement.
French Pat. No. 1,037,572 describes a relatively simple device in which the blade root is extended upward by a collar in the body of which is machined, parallel to the face of the disk, a triangular asymmetrical notch. The rotor disk has an axial flange on its upper face. The upper lateral surface of the flange has an asymmetrical triangular notch which is the reverse of the one in the collar. When the blade is in place in its groove, a locking part is inserted in the space between the two notches. This space is approximately parallelepipedal in shape and is extended at each of its longitudinal ends by a thin part forming tongues that are folded toward the faces of the blade collar. Radial movement is prevented by the corresponding faces of the notches working together with the locking part.
However, the device of the French patent requires blades equipped with collars and a flanged rotor disk, which are expensive elements both in terms of machining and of weight. Moreover, the locking element, which is itself expensive, must be considered a destructible part because in order to withdraw a blade at least one of the folded tongues of the assembly must be unfolded. The possibility of failure of the locking part caused by successive folding and unfolding of at least one tongue make repeated use of the locking parts described in French Pat. No. 1.037,572 dangerous.